3Com 4007, Implementation Manual, Page: 632 / 684

632 C
HAPTER
23: D
EVICE
M
ONITORING
A typical RMON implementation has two components:
■
Your system — Your system’s built-in probe functionality examines all
the LAN traffic on its segments, and keeps a summary of statistics
(including historical data) in its local memory.
■
Management station — Communicates with your system and
collects the summarized data from it. The station can be on a different
network from the system and can manage the system’s probe function
through either in-band or out-of-band connections.
The RMON specification consists almost entirely of the definition of the
MIB. The RMON MIB contains standard MIB variables that are defined to
collect comprehensive network statistics that alert you to significant
network events. If the embedded RMON agent operates full time, it
collects data on the correct port when the relevant network event occurs.
RMON Benefits From a network management console, traditional network management
applications poll network devices such as switches, bridges, and routers
at regular intervals. The console gathers statistics, identifies trends, and
highlights network events. The console polls network devices constantly
to determine if the network is within its normal operating conditions.
As network size and traffic levels grow, however, the network
management console can become overburdened by the amount of data
it must collect. Frequent console polling also generates significant
network traffic that itself can create problems for the network.
The RMON implementation in your system offers solutions to both of
these problems:
■
The system examines the network without affecting the characteristics
and performance of the network.
■
The system can report by exception rather than by reporting constant
or frequent information. That is, the system informs the network
management console directly if the network enters an abnormal state.
The console can then use more information gathered by the system,
such as historical information, to diagnose the abnormal condition.